When a semiconductor element is electrically connected to a circuit board, there has been conventionally used a method in which pillar-shaped terminals are disposed on an outer peripheral portion of the semiconductor element and an outer peripheral portion of the circuit board and the terminals are connected to each other by a wire bonding method. In recent years, in accordance with an increase of the number of connection terminals of semiconductor elements, there has been used a flip chip connection method of connecting the terminals while making surfaces of the semiconductor element and the circuit board face each other.
In the flip chip connection method, the semiconductor element having a solder applied on tips of its terminals is fixed on a head attachment, and the circuit board facing the semiconductor element is fixed on a stage. Then, by heating the head attachment by using a flip chip bonder, the solder is melted, whereby the upper and lower terminals are electrically connected at their tips. This terminal connection method enables the connection of a larger number of terminals than conventionally to realize performance improvement.
[Patent Document 1] Japanese Laid-open Patent Publication No. 2005-311250
Though enabling the connection of many terminals, the flip chip connection method has come to have the following problems in accordance with the recent progress of the miniaturization of the terminals.
In connecting the miniaturized terminals, mounting precision to the flip chip bonder is very important. Since the tips of the corresponding terminals are connected, there is a concern that, even if their positions are aligned when the tips come into contact with each other, their positions are deviated at the time of pressing and heating. Therefore, it is necessary to strictly set not only the control of the position of the flip chip bonder but also the pressurization control, the heating time, and so on.
The area of the mounted semiconductor element is on an increasing trend and the thickness of the semiconductor element is on a decreasing trend. In this case, a warp occurs in the semiconductor element, and when the semiconductor element is joined to the circuit board, a problem such as a connection failure of the terminals at a center portion of the semiconductor element becomes noticeable even though the terminal connection is achieved on an outer peripheral portion of the semiconductor element.